Titanium casting: The surface reaction layer of castings obtained using ultra-low-temperature molds.

Kikuchi, Hisaji; Onouchi, Makoto; Hsu, Hsueh-Chuan; Kurotani, Tomoko; Nishiyama, Minoru

doi:10.2334/josnusd.43.27

Cited by 14 publications

(3 citation statements)

References 3 publications

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“…Investment materials used for casting titanium are refractory materials in which the reactivity with titanium is reduced by using components with low standard free energy of oxide, such as alumina, magnesia and zirconium oxide. However, the formation of the reaction layer or oxide layer is not inhibited by improvement of the investment 10 .…”

Section: Introductionmentioning

confidence: 99%

The influence of mold temperature on the fit of cast crowns with commercially pure titanium

Henriques

Contreras²,

Mesquita

2005

Braz. oral res.

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Commercially pure titanium (CP Ti) has been widely applied to fabricate cast devices because of its favorable properties. However, the mold temperature recommended for the manufacture of casts has been considered relatively low, causing inadequate castability and poor marginal fit of cast crowns. This study evaluated and compared the influence of mold temperature (430 degrees C--as control, 550 degrees C, 670 degrees C) on the marginal discrepancies of cast CP Ti crowns. Eight bovine teeth were prepared on a mechanical grinding device and impressions were used to duplicate each tooth and produce eight master dies. Twenty-four crowns were fabricated using CP Ti in three different groups of mold temperature (n = 8): 430 degrees C (as control), 550 degrees C and 670 degrees C. The gap between the crown and the bovine tooth was measured at 50 X magnification with a traveling microscope. The marginal fit values of the cast CP Ti crowns were submitted to the Kruskal-Wallis test (p = 0.03). The 550 degrees C group (95.0 microm) showed significantly better marginal fit than the crowns of the 430 degrees C group (203.4 microm) and 670 degrees C group (213.8 microm). Better marginal fit for cast CP Ti crowns was observed with the mold temperature of 550 degrees C, differing from the 430 degrees C recommended by the manufacturer.

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Section: Introductionmentioning

confidence: 99%

The influence of mold temperature on the fit of cast crowns with commercially pure titanium

Henriques

Contreras²,

Mesquita

2005

Braz. oral res.

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“…In the present study, the VHN at the superficial surface of the casting was less than 400 in both generations. Kikuchi et al 26 evaluated the VHN of a Ti casting using MgO-based investment mold at different temperatures, and they found that the VHN increased with casting temperature. The microhardness value of the Ti casting reached 531 VHN at 600°C and only 473 VHN at the ultra-low temperature of –196°C.…”

Section: Discussionmentioning

confidence: 99%

The possibility of recasting of pure titanium

Lai

Chen

Wang

et al. 2017

Journal of Dental Sciences

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Background/purpose Pure titanium (Ti) has many advantages, such as high corrosion resistance and excellent biocompatibility. The mechanical properties of pure Ti are like those of type IV gold alloys. Furthermore, gold alloys can be successfully recast in dental clinics. The aim of this study was to investigate the possibility of recasting pure Ti. Materials and methods Magnesium oxide (MgO)-based investment that contained a 5 wt. % zirconium dioxide (ZrO 2 ) additive was used. An argon-casting machine (Castmatic-S, Iwatani) was used to recast pure Ti. The first generation and second generation pure Ti (50 wt. % new Ti + 50 wt. % surplus Ti) were used. Five specimens were fabricated and tested. The data were evaluated using two-sample t-test analysis (P < 0.05). Results The experimental results showed that recasting the Ti did not decrease the marginal accuracy, average surface roughness, Vickers hardness value of the superficial surface, and the thickness of the reaction layer. Conclusion This study clearly showed Ti could be recast when a 5 wt. % ZrO 2 additive MgO-based investment was used. This modified investment has the potential for use in clinical applications.

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“…Previous studies indicated that the thickness of the reaction layer in Ti castings varied depending on the investment 30) and the casting temperature 33) . The thickness of the castings can also affect their cooling rate because the heat of molten metal poured into a mold is absorbed faster for a smaller space, thus the solidification time of molten metal is shorter for a thinner casting 29) .…”

Section: Discussionmentioning

confidence: 99%

Surface characteristics and castability of Zr-14Nb alloy dental castings

et al. 2014

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The purpose of this study was to evaluate mechanical properties, surface characteristics and castability of Zr-14Nb dental castings. The mean 0.2% proof and ultimate tensile strengths of Zr-14Nb were approximately 68% and 76% those of Ti-6Al-7Nb, respectively, while they were comparable to Co-29Cr-6Mo. Elongation of Zr-14Nb was the highest of all alloys tested. The hardened reaction layer was formed on the surfaces of the Zr-14Nb castings. The layer consisted of oxygen and aluminum originating form investment. The castability of Zr-14Nb was comparable to that of Ti-6Al-7Nb. Dental castings of Zr-14Nb reveal mechanical properties that were within the range of the other dental alloys. Further improvements in castability and minimization of the surface reaction layer are needed for applications in dental prostheses.

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Titanium casting: The surface reaction layer of castings obtained using ultra-low-temperature molds.

Cited by 14 publications

References 3 publications

The influence of mold temperature on the fit of cast crowns with commercially pure titanium

The influence of mold temperature on the fit of cast crowns with commercially pure titanium

The possibility of recasting of pure titanium

Surface characteristics and castability of Zr-14Nb alloy dental castings

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